Vacancy Clusters Enable Configurational Matching for Selective Olefin C─H Activation Through Orbital Coupling

Selective oxidation of olefins offers an attractive route for upgrading light olefins into value-added chemicals, yet achieving high selectivity requires precise control over both orbital interactions and adsorption configurations at catalyst surfaces. Here, oxidative dehydrogenation (ODH) of 1-butene is employed as a model reaction to demonstrate that coupled bismuth-oxygen vacancy clusters on Bi₂WO₆ regulate the orbital coupling between surface Bi 6p states and the olefin π orbital, thereby reconstructing the adsorption configuration. In situ spectroscopic measurements combined with density functional theory calculations reveal that pristine Bi₂WO₆ favors a flat π adsorption mode dominated by C═C interaction, leaving the reactive C─H bond poorly aligned with neighboring W─O lattice oxygen sites. Vacancy clusters induce a tilted π adsorption configuration that spatially aligns the target C─H bond with the dehydrogenation site. This orbital-guided configurational matching promotes selective C─H activation while suppressing competing oxidation pathways. These findings establish orbital-regulated adsorption reorientation through vacancy-cluster engineering as a strategy for controlling selective olefin oxidation.